The present invention relates to an improvement in the field of press-fitting technology, which may be a method for the mechanical stabilization of a carrier material, for instance, of a printed-circuit board on a base carrier which, for example, may be a housing or another printed-circuit board. In this context, one or more press-fitted pins are mechanically press-fitted onto the base carrier, into the sleeves of the carrier material provided for this. The pins are usually deformed for this, both plastically and elastically. The elastic deformation in the press-fitting process has the effect of a restoring force, which then mechanically stabilizes the carrier material and the pins. In the case of electrically conductive contact partners where, for instance, metallic pins are plugged into a metallic coating in the form of a sleeve, besides the mechanical stabilization, electrical contacting is able to be made, as, for instance, for the electrical interconnection of plug pins with circuits on a printed-circuit board. Because of the mechanical and possibly also thermal stress during the press-fitting process, there is the danger of particles forming either on the surface of the pin or on the surface of the sleeve. These particles or “almost particles” become loose, possibly already during the press-fitting or because of downstream processes which are triggered, for example, by shocks to such a device. Other triggering processes may be, for instance, temperature stresses or alternating temperature stresses, or even the influence of chemical processes which may be triggered, for example, by increased air humidity or the attack of a corrosive medium. Such “almost particles”, which only become loose under the influence of downstream processes, are designated here as potentially loose particles.
A well known measure for decreasing loose or potentially loose particles is greatly to reduce the friction between the joining partners. Lubricants or auxiliary lubricants are used for this, for instance. In press-fitting technology, lubrication itself is a usual measure. As a rule, the formation of easily movable particles is reduced thereby during press-fitting. However, the creation of such particles cannot be excluded by the use of such an auxiliary lubricant. What is particularly undesirable is the formation of electrically conductive particles, which, as it happens, are frequently created in response to press-fitting technology. Such particles, which perfectly well, for example, reach an order of magnitude of ca. 100 μm or 0.1 mm, may result in short circuits on electrically unprotected printed-circuit boards.
Another measure for avoiding “straying” particles or chips is to encapsulate a unit produced by such press-fit technology, and thus to limit right from the start the freedom of motion of particles that will only become loose later or particles that are loose now. However, this measure is very costly (use of material) and has further disadvantages. In this connection, one should mention quite especially the poor cooling of the components. French Published Patent Application No. 2 753 044 shows such a design approach.